[dsraven]

sounds like an interesting plan.
is that wood on the floor? that will make it easy for fitting the trans under there
will your latch system work with the one piece window tracks etc in place? there is another thread on here lately where the guy is having some issues with latches, doing the same sort of idea as you have
just looking at the dash, it looks like there are some cracks around the speedo. maybe just paint? anyway, you may want to consider beefing up the dash/firewall a bit, if not already done, because the steering column looks (by the pics) like it is mounted fairly low on the column which leaves a considerable length left to become a big lever on the dash, if you use the wheel as a grab bar to get in or whatever. if you are going with a bigger inline engine you may need to do a bit of firewall work anyway.

looks like it will be a nasty unit when done. people are gonna get outta your way, haha.
keep posting up progress pics, it's good to see what you will come up with