Hi I Just tried Documents to Go on my Haipad 701-R and they charged me and it down loaded but would not install. It looked really good too. Would have liked to have it work. I too need something like that, but it appears to be only for phones.
Documents to Go is exactly what you want and describe. Unfortunately just like Microsoft Office, the newest version may not be compatible with earlier (read 1.5 and 1.6) versions of Android. You can find and d/load older versions which you can try before you buy. Otherwise verify at the Documents to Go will work with the Android version. Remember there are only four versions of Android. 1.5, 1.6, 2.1 and 2.2 right now. Any other number is the firmware build number.
I use HandBase and have for since it came out for Android. Works very well; however, it does not play well with Android's habit and method of working with available memory and back-ground applications. It works well on my Acer500 and the Evo.