I'm using Lazarus for my paldo-installer. Since Version 0.9.23-20071001 gtk2 might work really good. Here is a guide how to re-compile lazarus for gtk2.

gtk2 interface is under progress at the moment, but you can compile your apps with it. Here is how to do it:

1 - Go to the menu "Tools" >> "Configure Build Lazarus" on lazarus.

2 - Switch everything to none and the LCL to "Clean + Build"

3 - Select gtk2 interface and click "ok" button

4 - Go to the menu "Tools" >> "Build Lazarus" and wait for it to rebuild the LCL against gtk2

5 - Now you can switch your program to use gtk2 on the menu "Project" >> "Compiler Options" and switch to gtk2

6 - Rebuild your program

Now it will run using gtk2 =)