>> I am also aware that supporting them takes just as much effort as a large client. I don't like working in that market.

Intuitively, working for large clients should have its share of drawbacks that you may not see with smalls. They can throw their weight around trying to beat you down with regard to price, be slow to decide due to "red tape," and are typically hesitant to go with a smaller company (not sure how big your shop is) because of the risk of something happening to one of the principals. Probably other issues I'm leaving out, too, but have you not had some issues like these from time to time?