General recommendation - avoid it. A convenience of compactness - yes. Combos have been around for years, like TVs with VCR, etc. When part breaks, then you're let feeling youhave a piece of crap sitting there, & more often than not, are motivated to replace the whole works.
TVs generally should last longer than recorders. Stay separate.
Has anyone heard of such a product?
I've found that LG makes a 42-inch LCD and 50-inch plasma with a built-in DVR -- but I'd prefer something in the 34-37 inch range.