Best used turntable/arm combo for under $7,500.00

You have a serious amount of world class tables out there. You can go for a Direct Drive Technics SP10 variant. You can go for a Lenco based Idler drive by Artisan, or indeed a Garrard 401/301. These are both fuss free combos. Yogiboy is right about the SME 10. I happen to have an Amazon Model one - which is a superb fuss free belt drive turntable.
I recently acquired a Townshend Elite Rock that had a Mission arm and a Pickering cartridge all for £400 UKP. Truth be told, it's sound is absolutely astonishing, and I am gonna have to try it against my Amazon Model One. I'll be honest - don't spend a penny until you hear the Townshend Turntables!
A very good new deck would be the DPS model 2 - very much a best of all worlds approach
Whatever you do listen to as many decks as you can. All decks sound different, and go with what you enjoy the most.

At 7500 you really have a great choice of decks available to you. Try out a load of decks. You have some very nice Lenco and Garrard variants and you wil lfind they have a superb drive and 'boogie factor'. Direct Drives are very good at being neutral so hear some technics SP10's and similar decks, belt drives IMHO tend to have a wider range of variation - the SME 10 and 20 are very neutral - My own Amazon Model One has a very quiet backdrop and images superbly, although, having recently heard a Lenco variant - I think it doesn't time brilliantly. I personally regret not buying the DPS about 9 years ago when it came out first (I felt that I needed a few more reviewer approvals rather stupidly instead of trusting my ears) the DPS 2 has superb drive and boogie factor and was a rather superb deck for imaging as well. I personally found that the Platine Verier was a tad warm for me.
People tend to appreciate different things in sound, and that tends to change over time. At first I was crazy about imaging, now I am more turned on by timing.
I bought an Amazon Model One. I recently bought an old Townshend Elite Rock for £400 UKP with a Mission Arm and a Pickering XSV cartridge, I am yet to 'face off' against my Amazon Model One, but if truth be told, I have to say I am wondering if the Amazon Model One is as good, let alone better.
I have to say that Roscoeii is giving some excellent advice - listen to a Townshend Turntable before listening to more expensive decks, then listen to it at the end of your audition journey - you may save yourself some serious money.
I will say that budgeting for a good tonearm cable is mighty important. I have a Nordost Tyr, and plugging that in with the Shelter 501, was far better than a Transfiguration Temper V with the TCI cable.

Hi Pani - Everything you say is very itneresting. I have an EMT 950 - but I am taking an age restoring it - the problem is that it aint like a Lenco or Garrard in that with those it is fairly easy to take apart put back together - the 950 requires expertise - which is available from Hans Fabritius and others in Germany - for a price. I may just sell my 950 as it is gonna cost me too much to properly finish the restoration.
Back to the subject - it is very interesting what you say about the Linn. I was not a big fan for a long time, then I heard one that had had the Funk Firm mods, and had Naim amplification. It was absolutely fabulous - truly musically brilliant. I was unimpressed though by the Rega P9 which I tested around the same time as the Amazon Model One. I would have bought the Clearlight Receovery (not the basic version) had it been available when I bought my deck. I would like to listen to the Artemis SA-1 - I bet that it is cut from the same cloth as the DPS. I really like turntables that are compact and are not prone to being described as 'Audio Jewellery) like large transrotor decks (not that i criticise those who do like them - whatever floats your boat).
I liatened to the Platine, and whilst I was impressed, I just preferred the sound of the Amazon - that was then - who knows now... LOL
My sensitivity to timing is very much compunded by my loudspeaker choice - namely Yamaha NS1000M's which are very fast, and are sealed (none of the timing lag of ported speakers) - I always tend to like electrostatics and other planar designs as well. Couple all this to the fact that I also have a Lavardin IT which is a very high resolution, high speed design - it is no wonder that I have become so timing sensitive.
It is perhaps no wonder that people who go crazy over imaging tend to buy single ended amps and horns, and go for turntables that accentuate this.
I think that Rmarkus is about to start a wonderful journey, and should really get round to hearing as much as he possibly can - if he finds a cheaper deck that he enjoys more than an expensive one, then he should trust his ears and judgement - don't make the mistake of being over reliant on reviews and other peoples opinions - use them as a guide.