Another option if you can't find a LHD car and can't wait for a factory build is to consider a RHD car and have it converted to LHD.

I've done that with my own car (a Hawk) and it's possible, the earlier the chassis the easier it is BUT it's a compromise as the Hawk chassis is not symmetrical around the centre line, just like the original. A converted car will have a narrower footwell than is ideal. If your feet are larger that size 9 (EU 42) it probably won't be safe. Size 9 and below you're still going to need race boots.

I can't comment on the possibilities of converting a LB for RHD to LHD other than to say their steering rack, with it's centre pinion, should make the job a little cheaper. Relatively.