is there such a thing?  

like this?
I don't know who did this piece but i just came across it today...

There's definitely such a thing.
You just have to hunt down an attractively designed version of the thing.
http://www.varologic.com/blog/post/2009/05/25/Laptop-Stand-from-Notabble...

.
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http://www.prohoists.com/Rolling_Computer_Cart_Desk_Laptop_Bed_Chair_Tab...

this?
this?

IKEA
do this:

When I
owned my bookstore, I used to receive the Levenger catalog which was full of nifty book-lover's gadgets. They have a tilting desk like you describe.
(As I was posting this, I noticed it is actually manufactured by Herman Miller, known as the "Scooter" desk.)
http://www.levenger.com/PAGETEMPLATES/PRODUCT/Product.asp?Params=Categor...|Level=2-3|pageid=734

Yeah-- I too thought of Leveger, Riki
But they don't seem to make something that's cantilevered, like Heath wants.

close but no cigar
Heath,
The Fritz Hansen - Little Friend is a small adjustable (no swivel or tilt) cantilevered table of good quality.
My favorite is the Notos for ClassiCon. It is truly more of a lectern or book display, but the design is wonderful.

Tons of them out there.
Click the link below to see a few thousand of them. Most are designed to be used over beds rather than sofas, so check closely to make sure that they adjust low enough for you.
Unfortunately, most of the ones that tilt don't look very pretty. Of the non-tilting tables, I think the Little Friend is the nicest, but it's VERY expensive. Room and Board used to sell (and maybe still sells) a non-adjustable copy called the Edit Table for about 10% of the price. And of course Eileen Gray's table was also designed for that sort of application, but your laptop would have to be pretty small to fit on it.
http://www.google.com/search?q=(overbed+OR+%22over+bed%22)+table