Highchair - Bishop,CA

Try the Fisher Price Space Saver highchair

http://www.toysrus.com/product/index.jsp?productId=2508005

I highly recommend looking at the Fisher-Price Booster Seat:

http://www.walmart.com/catalog/product.do?product_id=2626212

I think I got mine at Target, but most anywhere sells them. Extremely easy to set up, easy to tear down & goes anywhere. We bring this seat to grandma's, restaurants, you name it. My child is nearly 3 years old & he still sits in it. It adjusts in height, which is why I needed this since our high chair wouldn't fit under the table we had - he always had to be eating away from the table as he got older.

This way he can learn good table manners & sit at the same height as the rest of us.

Try the Bumbo or the Bebe Pod. I've heard they are nice. Not sure if that is exactly what you are looking for, but check out this link comparing the two: http://familytravel.suite101.com/article.cfm/bumbo_vs_beb...
I have a 3 & 1/2 month old daughter and she is close to sitting up on her own. When she does I will likely get one of these.
Hope this helps! :)
B.

We had the same issues when our girl was a toddler! Babies R Us has quite a few =)

http://www.toysrus.com/family/index.jsp?categoryId=2256183

I haven't seen a booster seat that goes into a high chair, but we had a high chair where the height of the tray was adjustable - it was the Fisher-Price Healthy Care high chair. My youngest daughter is really tiny for her age, and has always been that way, and I found the adjustable height tray to be very helpful.