Subwoofer recommendation for swarm

I`ve been using the Dayton SA 1000 subwoofer amp for a few years now powering a Revel sub.
The sub has a 15" woofer in it. I`d like to do a swarm but still use the Revel.
Is that feasable ?

Sure is. I'm using 2 Daytons to drive 4 Morel 10" subs. Two ported, two sealed. Plus one Talon Roc powered sub. There is absolutely no problem mixing sub brands, drivers, enclosures, amps. You can add subs and drive them with the Dayton, or add powered subs, either way. Just whatever subs are used be sure to know their impedance and know how to connect them in series or parallel to yield the total impedance you want and your amp can handle. If you do run multiple subs I suggest comparing the different loads. Most prefer the tighter more articulate bass of higher impedance (16 ohm) than low (4 ohm) which while it yields a big more power tends to sound a little tubby compared to 16.

While my setup uses two the same four can be run with just one Dayton just fine. While low bass with a DBA is impressively 3D and seamless with the rest of the sound stage, this bass imaging localization is all coming from mid bass on up. All subs can be run mono and nothing whatsoever is lost. Finally, don't waste money on sub speaker cables. Duke himself tipped me off to this and while this was hard to believe its true- which I guess being Duke almost goes without saying.

Bigger is better. Bigger magnet, bigger voice coil, better faster response. Bigger cone, more bass. Bigger box, well you get the idea bigger is better.

That said, impedance and efficiency are important. Especially if you will be driving all 4 off the one amp, then you want to be sure it will be able to drive them all at once. With mine, thanks to having two amps I was able to compare them wired for 4, 8 and 16 ohms. While they deliver more power into 4 the bass was much better by far at 16. According to Duke none of his customers who have compared have preferred 4 ohm. Something to keep in mind when comparing speakers.

How do you distribute the subs? Can they all be on the same side of the room or on just two walls?

Well mine are just on two walls and work just great. I've moved them around experimenting a bit but with my system its almost impossible to have one on each wall. Well I could by putting one or two up near the ceiling! Which by the way according to DBA theory would be better. In practice however mine works so well I just can't see going to much effort trying to improve it.

Mine are on the left and right walls, each one a different distance from the corner. Plus I have one powered sub almost exactly in the front left corner. None of these is localizable, to the extent I often times have to touch the cone to be sure a sub is really working. Really low bass is amazing- it sometimes is so diffuse you feel the whole room immersed in it, yet other times its imaging the drum or bass guitar precisely on the stage right along with everything else. Seamless.

Tim aka noble_100 has a room almost identical to mine (one foot less each way) and he went through a very definite procedure to locate each one, which as I recall resulted in one very near each corner. 

Remember speaker location is only half the equation. The other half is listener location. The other 50% as Yogi Berra might say is having four.

My DIY Swarm was built earlier this year. Based on Duke's and using two of the Dayton amps he recommended above, together with four 10" Morel woofers from Parts-Express the total cost excluding Rosewood veneer was not much more than $2k. You could easily build it for less than $2k simply by using one Dayton amp instead of two. Two are not really necessary, the extra amp just adds more flexibility. Based on my experience the first thing I would cut to save money is the extra amp.

Even if you have your own shop and skills and materials its still hard to beat the kits. I have all that, including the MDF just sitting there, yet still went with the kit. Savings in sawdust alone makes it worth it. Although if you have the time and inclination to dig into it you might be able to learn enough to make your own enclosures custom for your particular situation, which might repeat might be worth it. 

I would also seriously consider anything Duke has to say on the subject. He was a huge help to me and always recommending whatever would work best for me, never pushing anything in particular even though it would have been much easier to just try and sell me his Swarm.

There are a lot of options. By far the most significant decision you can make is the one to go with a distributed bass array. The DBA is so inherently better than everything else its hard to believe until you experience it first hand.