Hi!
There are some available….
I know, the itp A3 (if you can find it… but, as you said very expensive)
The Hypetac P1A SS (24$ at shiningbeam) (see review here Review: Hypetac P1A SS (1x AAA))
The NLight AAA (review here Review: N Light AAA 3 mode Stainless Steel) But I think the price goes above your budget
The Fenix LD04 SS (again too expensive)
The UltraFire T1 for 20,30$ (I think it is made of SS) http://dx.com/p/ultrafire-uf-t1-cree-xp-e-r5-80lm-2-mode-white-light-mini-flashlight-silver-1-x-aa-168331?Utm_rid=43033281&Utm_source=affiliate
But I think you should go fot the BronteRA01 SS for less than 25$ http://dx.com/p/bronte-ra01-cree-xp-g-r5-80lm-3-mode-led-white-light-flashlight-1-x-aaa-1-x-10440-113459?Utm_rid=43033281&Utm_source=affiliate
(review here Review: Bronte RA01 Stainless Steel)
I think the bronte is the one you need, the circuitry has a good regulation too.
There are more…. but… I can´t remember now… I will update if I find more!