I just ordered a pair of reproduction Lucas P700 tripod headlights. These are made to take a modern halogen bulb so I'm expecting they should work OK.
$226 Aussie ($126US) including bulbs. I got them from a guy in South Australia that just deals in classic car lights and electrical stuff. He imports Lucas gear from the UK. I also ordered a set of Lucas 691 tail lights and front marker lights.
I'll post a pic when they arrive.
Here is his web page, I think he has distributors in the US as well.
http://www.classicandvintagebulbs.com/index.html
Cheers