What about filters.
10 stop ND filter is awesome. I love that thing, one of the best hundred dollars I have spent. If you really want to burn maoney get the SingRay Vari ND filter so you can change how much darkness you want.
Go for Cokin filters too, gradual ND filters. If you have money to burn you can go for the z-pro size and get rid of any vignette.
Buy a converted IR camera body.
Sell me you 85 1.8 for $250 and then you will have $600 to spend. :P
It's not a big job. Here is a shot of it after about 6 hours work. I have been busy with other things and haven't finished it yet. Doug already had the mast.
His website is dougthompson.net He does commercial stuff. He has a smaller one that goes to 35 ft, and it is portable. It fits in a Reese trailer hitch socket, or mounts on a big tripod base that he built. It's more portable for shooting courtyards and the like.