Question for cell phone know-it-alls

I don't carry a laptop, and I'm not interested in buying an expensive phone with an expensive contract.

On the other hand, I'm occasionally in places, or at events, where I'd like to tweet or moblog extensively, and thumbing text messages into a small phone keypad is just a pain in the ass.

So, here's my question: Is it possible (and if so, how hard would it be) to pair up a cheap Bluetooth keyboard with a cheap phone (I'm looking at the Motorola E815 and the LG VX8300)?

I want to keep my total device expense under $100 ... hopefully way under $100. My prepaid cellular provider is selling the Motorola for less than $50 and the LG for damn near nothing.

I don't plan to use my phone to browse the web or as as a game machine or MP3 player or anything like that. I just want to be able to talk on it (occasionally!), text message from it and take/send pictures with it. They don't even have to be especially good pictures (the Motorola has a 1.3 megapixel camera; the LG's camera is VGA).

The idea is that I generally tweet/moblog from settings where I'm at liberty to sit down and spread devices out in front of me for a time. I'd be happy to carry a keyboard, especially if it's one of those foldable jobs, with me, if I could plug that keyboard into my cell phone and start updating Twitter/TwitPic, Blogger or Facebook via text message using it, instead of holding the tiny phone in both hands and scrolling through letter combos. I'd rather not carry a laptop for such things (and my current, wonderful laptop is "headless" -- the screen doesn't work and I use it as a monitor-connected desktop -- in any case).

The last time I live-blogged an event using my phone, I had to pay more attention to the "typing" than I was able to give to the event itself. With a real keyboard attached, that would change in a big way. So ... can I do that?

If not, I may go ahead and spring for something like the Cricket MSGM8, but frankly that's more phone (and more phone service!) than I need and the tiny QWERTY keyboard looks almost as aggravating and time-consuming as a regular phone keypad.