This is a cool idea! I can't really think of a way that I could use this, but that's never stopped me from trying a quick hack in the past. Without further ado, I give you a JohnX exclusive "Crappy Hack!"

What you need:
0) some method to be root: becomeroot, openssh-server or r&d mode.
1) osso-statusbar-cpu (search for it on gronmayer.com/it)
2) libxmu6 from: http://repository.maemo.org chinook/free
3) flite
4) My freshly compiled xclip attached to this post.
5) this script: Copy and paste this text into "Notes" on your tablet. Then open the menu, select Format -> file format -> Plain text and save it to the Documents folder as "selection2speech"

What to do:
1) Install osso-statusbar-cpu and libxmu6. To install libxmu6 you will need to use the command line ("X Terminal"). As root type this:
apt-get install libxmu6
2) install xclip, attached to this post. You will need to do so from the command line as root:
dpkg -i xclip_0.08-7_armel.deb
3) When you see the osso-statusbar-cpu app in your status bar, tap on it, then Settings... -> Commands -> New. For Description put whatever you want. For command type this exactly:
sh /home/user/MyDocs/.documents/selection2speech.txt
4) Now try it out. Hilight some text then click on osso-statusbar-cpu, find the command you put there and tap it. A hideous robotic voice should read the selection. If it doesn't work you get to keep this pieces. What a deal!

If anyone wants to package this better go ahead. It won't hurt my feelings, I prmoise.

-John