I don't know if you checked, most phones w/ external memory card slots allow you to store your text messages on the card directly.
If there is such a thing? I have a Krzr K1m and it only holds around 100 texts [it can vary and only hold 80 or 90 or 110 some days]. I hate having to rush to my computer all the time to save the ones I need. I want a phone that holds more so I don't have to do this all the time. Is there one?