First of all, thank you for looking at my post!

I recently purchased a cheap 1999 Norco Scrambler from a local bike shop in Windsor, ON (Courtesy Cycle on Sandwich St.) and have made it a temporary hobby to upgrade most of the parts. I have replaced most things without a hitch, but I need some advice on the bottom bracket, crank and front-derailleur.

I bought a Shimano Deore LX Octalink (FC-M572) crank from Nashbar.com recently, without much knowledge of BB's and so on. After it was shipped, I learned that (my fault here) my spindle needs to be 68mm English (which it is) and 121mm or 126mm in length (which it isn't - it's 124.5mm). I haven't bought a BB yet, but the BB-ES51 is the recommended part and it measures 68mm x 121mm. Is there anything I can do to make this crank work with my setup? If so, how?

Also, I have no idea which front-derailleurs are compatible with this bike. I do know that at present, I have a "clamp-on 28.6mm" derailleur. Is it possible to replace this with a Shimano XTR part (or similar quality)? I have so far upgraded my other parts (aside from the crank) to: a Shimano 6/7/8spd. Alivio rear-derailleur and a 7spd. Shimano HG70 cassette.

In closing, what BB will work with both my 68mm x 124.5mm spindle and a Shimano Deore LX Octalink crank? And, which front-derailleurs are compatible with both a 7spd. setup and are clamp-on 28.6mm?

Thanks in advance (I am dying to get out and ride this thing!)
Robert