Gaines, I have a backup harness and am 6'6" tall and 250 lbs, are you bigger than that? I would be more than happy to let you use my extra one while we ride...
As for a trainer kite, try EBay. Also Ikitesurf's buy/sell section is a possibility. Just make sure to read the 'scam alert' thread on this forum before buying on either site. Or you could go to
www.oceanextremesports.com or
www.watersportswest.com if you want to buy a new one (they are a bit expensive, about $250).
www.bestkiteboarding.com has some less expensive new ones...
Good luck and feel free to send a PM if you have any other questions...