i have never found the 3.8mm or 4.5mm bits in the store. however, i have found the others in the stores. it was mentioned earlier that some are cheap and found the ones at dealextreme a little subpar. i wish the quality of dealextreme was a bit better because the price is unbelievable

here are the alternatives that i got for myself in usa. less shipping time than dealextreme (no 2 to 3 week wait)..

3.8mm gamebit and 4.5mm gamebit
http://www.newelectronx.com/proddetail.php?prod=gamebit

Here's a cool set (3.8mm and 4.5mm included with Xbox tool):
4.5mm Gamebit Gamebit 3.8mm Oval / SA-8600 Reverse Torx
http://www.newelectronx.com/proddeta...bit-oval-sabit

Screwdriver Bit Set Slotted, Phillips, Star Driver 11 piece - only $1.99
http://www.newelectronx.com/proddeta...llips-star-set

i would be remissed without mentioning the whole set:
Security Bit Driver Tamper Resistant Set
http://www.newelectronx.com/proddeta...er-bit-set-100

I dont have the whole set yet, but thinking about getting it. I do have the others and i must say the gamebits are the best i have ever seen and used. definitely worth a look