Hey ajradeon, I bought my kit from my mate Ron Wilson from ebay. He owns a company and he can do you an excellent deal. Bid on this kit and once you've won it, tell him to quote you on a Sylvania Metalarc HSI-TD 250W/NDL UVS lamp (has built in UV filter) and 2 X Lampholders for that lamp. He won't charge extra for postage. And delivery is extremely quick. You won't get a better deal. Mines was about £60 the whole kit including the lamp, holders, ballast, ignitor, capacitor and the delivery.
All those other lamps you've posted will still require ballast and all that. If you've already got the ballast and all that and just require a metal halide lamp, then just email him and ask for a quote for just a lamp. He never lists his lamps on ebay but he does usually have stock of those.
I've read some of your other post and I know you want the metal Halide for your OHP. You don't really need a lamp in an enclosure to fit in a OHP. Take a look at the link below. And that's fitting the same style of lamp that I've mentioned above - the 250W NDL HSI-TD. You'll just have to find a place to mount your ballast and Capacitor (probably by removing the transformer).