Check ebay regularly, and also the web finds board here on LG. Low wattage MV appears from time to time for very good prices, most of mine have been from ebay.
If you live in a 230v country, one option you have is to import a 12v pure sine wave inverter that does 120v and run it off either a deep cycle battery or a strong 12v power supply and you'll be able to run the North American lamps and gear which might be more common to find online.
Rommie does this I believe. This works best if you intend to have your lamp set up as a demonstration and of course only attempt if you can do so safely.
For 40/50 watt mv, a 39w magnetic mh ballast works a treat with ignitor removed.