hmm maybe you didnt look, i found one today on ebay for 1195, and earlier this year when I thought my tranny went, I did all the research on the swap, speed cal and all, and it could have been done for under 2K. Most people wouldnt need a speedcal, only guys without the electronic speedo. Many parts can actually be reused, including the crossmember, the shift fork, the clutch cable, the driveshaft (with shortening/new yoke). And they will also take a t45 for a $300 if you dont have a T56 to give to them.
Tranny:$1195+$100 core difference for T45 return
Driveshaft reworked: $150
Reverse Lockout: Almost Negligible
Shifter: About $50 for a stock one, from someone who upgraded their stock unit
Speedcal: $100
http://cgi.ebay.com/ebaymotors/T56-...020QQitemZ300162867896QQrdZ1QQsspagenameZWDVW
so a grand total of $1550, doesnt seem like it, "costs so much" to me, especially if you plan on shelling out over 1K for another 5 speed with a useless 5th gear