Do you have an E2D with a Domed lense, or a flat one.
If its domed ( Old style) than you could pull apart a P61, and fit that in;
Or a P91...but you will have to wait a while untill you can buy (two) IMR RCR123's to power it...Due out in a while ( hopefully)
If its flat then I think you have to file the bulb down, and a few other bits.
But it will get stupid hot on the P91. ~( I used to run mine on two unprotected RCR123's but it was silly and dangerous ( Bright though for the size
)
Do a search for E2+ here on Cpf. Its an old mod, before lumens factory etc.
Or you could use a socket built buy five Mega to run a TL£ lamp of two RCR 123's.
(I think I have a spare somewhere if you can't find one)