I'd like to use a SD Card Module with my Pro Mini 3.3V
Unfortunately all modules that I found on eBay so far have a voltage regulator built in (mostly cheap LM1117 with a big dropout), so they need a minimum of 4.5V.
I was just wondering what you guys do in this situation? Do you unsolder the voltage regulator?
So use a breakout kind of module, with just the SD card socket on the board.
I think Sparkfun carries some.
Promini's 150mA regulator cannot supply enough current to power it - you'll need another 3.3V supply.
CrossRoads:
Promini's 150mA regulator cannot supply enough current to power it - you'll need another 3.3V supply.
I already have a 3.3V supply. My whole circuitry runs at 3.3V. It's just that this stupid module wants (at least) 4.5V.
See if some of these are just the socket on a board, pics are not opening for me.
https://www.sparkfun.com/search/results?term=sd
They have a breakout board for $9.95 - which they most probably get from China for $0.05. Sparkfun is a boutique and I won't by their stuff.
If you have a module with 3.3V regulator and want run it at 3.3V you may remove the voltage regulator (desolder) and wire voltage regulator's input and output together (with solder blob jumper or w/ short wire).
Or, which works too, simply short voltage regulator's input and output.
Mind you cannot use the module with 5V then (mark it as for 3.3V only).
No warranties of any kind 
I have found MicroSD breakout boards on ebay for 3.3V.
Here is a $0.99 module.
It appears to have pullup resistors and filter caps. There are several versions of this board on ebay.
Thanks a lot fat16lib. That's what I was looking for.