Crossbar is not needed. Wither have a slot to slide the board in, or have a clear cover to that opens and closes to access the cards.

I prefer no crossbar - just being able to slide the game card into the frame via a permanent slot

I agree with Kim on this one, the cross bar is too fragile for little kids who are tough on their toys.

I'm inclined to agree with Kim and George and add that in addition to getting lost or broken, it also could poke kids or pets in the eye. It's too thin, long, and mobile to be put on a younger child's plaything.

Here's the link to a video explanation...
http://www.youtube.com/watch?v=iSRuNF9Rg5E

I think the crossbar should be permanent. In fact, you don't need it at all.
If this works like a frame, the cards could be inserted from UNDERNEATH the frame, just like when you put a picture/photo in a frame. There should be a clear piece of plastic (just like a real frame, except real frames often use glass) to protect game cards, plus it can enclose all the pieces when not in use.
Then, you can have a tray/box underneath that can hold all the pieces and game cards! If you flip this box upside down, you can have a plastic border that can hold the card in place. When you put the frame on top of this tray/box (upside down), then it will hold the game card in place. Flip it back over when you clean up and it can store all the cards and game pieces. When I tried to explain this to my wife, she was like, "HUH?"
So, I made a quick prototype out of cardboard, filmed it, and now in the process of uploading it to YouTube. Stay tuned for the YouTube link, as it takes quite a while to upload and process. Filmed it in "HD." :)
This could also work with the Organic Blob, just has a different shaped frame.

I think the crossbar should be permanent. In fact, you don't need it at all.
If this works like a frame, the cards could be inserted from UNDERNEATH the frame, just like when you put a picture/photo in a frame. There should be a clear piece of plastic (just like a real frame, except real frames often use glass) to protect game cards, plus it can enclose all the pieces when not in use.
Then, you can have a tray/box underneath that can hold all the pieces and game cards! If you flip this box upside down, you can have a plastic border that can hold the card in place. When you put the frame on top of this tray/box (upside down), then it will hold the game card in place. Flip it back over when you clean up and it can store all the cards and game pieces. When I tried to explain this to my wife, she was like, "HUH?"
So, I made a quick prototype out of cardboard, filmed it, and now in the process of uploading it to YouTube. Stay tuned for the YouTube link, as it takes quite a while to upload and process. Filmed it in "HD." :)

I would worry about the piece holding down the sheet getting lost.

Simple and functional. The crossbar piece would need to be of decent quality so it doesn't break. There should also be a non-slip material so the game card doesn't slide around in the unit.

I worry about the plastic frame getting broken on this one. Looks cool, but little kid games need to be pretty tough.