Bryan wrote:
Second upgrade may be to convert from 7spd to 8/9spd. Currently the
rear hub is XT. Looking around I seem to have 2 options, build up a
wheel based on a new hub, or get a new 8spd freehub body.

There's a third option, an easier option (assuming a Hyperglide freehub):

Use 8 sprockets from a 9-speed cassette, with 9 speed-spacers.

See http://www.sheldonbrown.com/k7.html#up7 - 8 Of 9 On 7

~PB