I'll add my .02 since I was recently in your position. Granted I wasnt doing a bad ass swap like you but I was nevertheless elbows and assholes deep in a rebuild of my DD. I was so close to completion and yet so tired of of it all and wanted transportation SO BAD. I was riding a bicycle for everything I needed to do, now thats bad.
I was litterally holding the wrench in my hands to start taking her apart for the part out...and I stopped, walked away for a day, and came back with what in my mind was my last push to finish her. I Sold a few extra parts to be able to afford the last few things I needed and with almost no help from anyone, got my motor back in my car, finished off the details and got her back on the road.
I will never know what it would have been like to part it out, but I can tell you that even my darkest hours now seem worth it to drive my Supra again, and I still have yet to turn up the boost past 5lbs. (about 200miles on the clock and ticking). However, the best feeling I get is from knowing I had the fortitude to stick it out. If you've followed my build at all you would understand what a rollercoaster its been.
I guess what Im saying in my usual long winded way is: Keep at it! You will feel so much more rewarded if you stick it out. Not only will you prove to yourself and the community that you have what it takes to complete a difficult build like yours, but you will also have one of only a handful of mk3's with the mighty 2JZ in it. That is an accomplishment that I and alot of other guys on this forum only dream of doing.
::salute::