I did a quick look at loans starting 07/2009 and ending 04/2013 using Lendstats:
For credit card and debt consolidation 60-month loans between $30000 and $35000, the loss rates are as follows:
D: 8.5%
E: 9.7%
F: 11.3%
G: 10.7%
For the same loan categories of 60-month loans up to $29999, the loss rates are as follows:
D: 7.9%
E: 9%
F: 10.9%
G: 11.8%
It seems that $30,000-$35000 D-F loans are generally speaking just a tad riskier than smaller loans, but by not much.