I have been wanting to build something like this for a while. I recently ran into these MA 10p drivers at a thrift store and decided to go for it. I already had the Eminence 15 drivers. I still have some work to do on the paint job and figuring out how the final back braces are going to look. Right now I am using shelf brackets.
I have been playing around with active and passive crossovers. They sound great. The MarkAudio drivers are really special IMHO. I have the MarkAudio low passed at 250hz 1st order and the Alphas are crossed at 225 1st order.
Please excuse my messy room and my poor carpentry skills.