Other ballasts (HX type, no capacitor) should fit, but you might have to use a tiny Chinese one. I remember seeing these for sale at Lowe's years ago for around $80. There was a metal halide version too, I assume 70w....I've seen some installed, but never for sale. The 100w and 80w mercury versions were most common (I have both), and they had a photocontrol mounted in the rear corner (where it usually wouldn't see daylight if mounted on a building).

Ahh, I was planning on using a Venture 70w MH ballast I had lying around but it might be a tight fit getting the cap in. Mine didn't have a PC installed but the knockout for one was in the location you mentioned.

I always liked these Regent floods. Too bad they discontinued them.

I converted one of these to 70w psmh, the huge ballast barely fit. A 100w mv ballast should fit ok though.

Ahh, I don't have a real 100w merc ballast but I guess removing the ignitor from a 70w PSMH ballast will leave a bit more room inside. Currently it's still 70w HPS.

Well let's put it this way.... the ballast was so big I had to almost force the reflector back in.