With TC2.2 you can put text on the desktop with everything included in the base.
aterm knows some nice tricks:
aterm -tr +sb -bl -sh 99
Used this in conjonction of your wm config, you maybe be able to achieve what you want.
For example, if you use jwm:
1 - add some group configuration magic in the configuration file:
<Group>
<Name>backterm</Name>
<Option>layer:1</Option>
<Option>notitle</Option>
<Option>noborder</Option>
<Option>nolist</Option>
</Group>
2- restart jwm for the option to take effect.
3- create a symlink with name you specified in the goup config:
ln -s /usr/bin/aterm backterm
4- and then finally:
./backterm -tr +sb -sh 99 -fade 100 [-e my_program...]
tadaaaaaa!
tip: you can use the -g flag to specify the position on the desktop