Space is not an issue, time is not even an issue, cash is not such a huge issue either,but, if only I was not such a putz or a clutz when it comes to anything where one has to use tools, be it power or manual. I would dearly love to have a go, but then again the missus would probably tell me to work on the house rather than add another pair of speakers to the clutter.
I would only attempt to build a pair if I could improve on what I already have, maybe I could improve the BLH Nagaoka's used with Fostex FE168Sigma cones, but there would be no way on earth I could improve (or even get remotely close to) the wonderful KCS 150's that adorn my ears and eyes every day.