That's a bummer to hear Chop, but you have to do what is smart for yourself. Time is exceptionally valuable and it sounds like that is the biggest sticking point (it always is for me). Have you unloaded the SEOS-24's? How many did you get?
Honestly I still think that you could make something happen on the DIY front that scales back the cost AND time while not sacrificing significant performance.
First, I would stick to simpler surrounds (I can't recall if you were still looking at SEOS-24 surrounds). Something like passive SEOS + 4550's an a single TD15M. You could even use a flat pack or baffle kit.
Second, I would downsize to dual TD15M's with the SEOS-24 in between. It would be very similar to this speaker which also uses a BMS coax on a similar sized horn: http://www.professionalhomecinema.com/loudspeakers/scr-2215sm1/
The surrounds would be passive and the LCR's would be hybrid passive/active DSP. Simple passive between HF and mid on horn. Active DSP between woofers and horn. I would suggest either a Behringer DCX2496 or MiniDSP 8x8. For amps, you could do 3 Behringer EP4000's. Your LCR amps + DSP would be $1200-1500...less than the cost of a single amp+DSP in your prior plan.
The final question is box building. If you are building your own room, you might as well build these enclosures. Since they will be behind a screenwall, they don't have to look pretty. 2x2's are good for bracing. Have the baffles CNC'd.
Of course, if you have just lost the will, I understand. I just think you could get 99% of your original planned performance for no more than about 20% of the cost and complexity.
One other thing, I would suggest farming out some of the HT build. Many of those tasks are far more time consuming (and relatively cheap on labor) than building 3 speakers.