Myr-myr,
Would one of these Table-Mates work for you?
The top is 15 X 20, and height is adjustable.
http://www.rkdm.com/tablemate/tablemateaction.gif
It actually folds up for compact than shown in the demo .gif
The one I have is just a few months old, and either used literally 2-3 days, or totally unused. (Long story, over ordered and ended up with extras; I can bore you with the details, when you come by to pick it up, if you wish to have it) ;-)
I’ll let you keep this, for free, the only thing I ask is if you don’t need it later, that you donate it to a worthy person/cause/organization.
Let me know here, and if you want it, I’ll call you.
Mike