Actually, just so you guys know- the E2 lamp is just a refitted P60 as the E1's is a refitted R30. I'm not sure that's public knowledge, but they didn't tell me NOT to keep quiet about it, so there ya go.
I've been meaning to rip apart a 61 just to see if I could retrofit the lamp to a base, but haven't had the time. Not sure it'll work right, but it's worth a shot if anyone has the time or inclination to waste $20 if it doesn't work.
As for the aluminum- yep- if one of the lamps blows (explodes, not burns out) you'll have fragment scars everywhere on the reflector. Those little lamps are at over 1000PSI and when they blow- POP!
All the reflectors cannot be changed- the E1, E2, 9N, 8NX and M6 (off memory here) all have fixed reflectors- and require a new bezel if things go TU.