To Buy or to DIY, here is my question

If I were to do this without DSP I would keep the drivers in separate enclosures as small as possible even open (except for the woofer). This will allow you to move them relative to each other. Using the calibrated microphone you can measure the group delays and move the speakers to get them all time aligned which if you are lucky will also get them phase aligned. This should be done outside to avoid reflections that can confuse things. Once you get the locations figured out you can mount them in a framework maintaining those relative locations ala Wilson.

@chorus , by all means! If you are looking for point source speakers DIY is the best way to go with a few caveats. I would stick with drivers that have the same radiation characteristics. Putting a ribbon tweeter (line source) in a point source loudspeaker is going to significantly change the frequency balance with even small movements in the room. Keeping the drivers phase and time correct is not easy and frequently results in some very complicated crossovers which are impossible for the novice to design. You can stick a basic crossover in there but you will not get the best imaging. You can not do this well without a calibrated microphone system. Depending on luck does not work well with speaker design. If you do not want to get involves with DSP you will have to get very inventive. But, that is the fun in it!

@chorus , lots of interesting comments here. I will put on my woodworking teacher hat for a moment. Woodworking tools are extremely dangerous. Even the lowly little router can bite you badly if you do not know how to handle it correctly. You have to understand fully every machine you use, how it works and how it is likely to injure you. Even expert woodworkers get hurt once in a while by unforeseen circumstances. Hand tools are just as dangerous. I know one fellow who spent two weeks in hospital after skewering himself with a Japanese paring chisel. He violated one of the primary rules of woodworking, you NEVER cut towards yourself. If you have no woodworking experience or no access to a supervised shop but you really want to DIY you are way better off building a kit and there are many good ones available.  All the heavy machining has been done so it is just a matter of glue  up and finishing. There are finishers out there who will put a brilliant piano lacquer finish on for you.  

As an example of how complicated a certain process can get lets look at cutting a perfectly round 10" hole, one good enough to be visible. You can scribe the hole with a compass so you know where to cut, drill a 1/2' hole within the diameter of the 10" hole then cut the plug out with a jig saw. What you will get is a chipped out mess even if you have the steadiest of hands. The best way to do this in a small shop is to drill a 1/8" hole dead center of where you want your 10" hole to be. You get a hole cutting jig for your 1 HP router and attach it to the base. Load a 1/2" downward cutting carbide spiral bit and set the depth of cut to 1/4". Pass the 1/8" pin supplied with the jig through the 10" hole in the jig (there is a series of holes for various sizes) into the 1/8" hole you drilled. With the router just off the work start it up and plunge it into the wood. Make your circle spinning it around the pin and release the trigger. When the router comes to a dead stop remove it from the work. Now you have a perfect circle with a beautifully finished edge. If you had used an upward cutting bit there would have been tear out all over the place. Why not cut all the way through the 3/4" board? It is too large a cut for a router that size. You will get shudder which will ruin the cut. Now you drill a 1/2" hole anywhere inside the circle and use your jig saw to cut out the plug staying 1/8" inside the finished edge. Finally, you flip the board board over, put a downward cutting spiral carbide bit with a bottom bearing follower into your router and finish off the bottom of the hole following the top, pushing against the cut. Now you have a perfect 10" hole and you can use this piece as a jig to cut out any other 10" holes you need to cut using router bits with bearing followers. You just spent $600 on tools and tooling forgetting about the knowledge to do it right. 

I am not trying to scare you. You can make an excellent sounding loudspeaker but unless you have a lot of experience it is not going to look so hot and hopefully you will be careful enough not to get hurt by reading up on each tool you use and making test cuts to get the hang of it.