Hi,
I have found a little information which may be useful to u.
supports 20,000 unicast routes (Cisco Catalyst 3750G-12S)
supports 11,000 unicast routes (Catalyst 3750G-24TS, Catalyst 3750G-24T, Catalyst 3750-24TS, Catalyst 3750-24PS, Catalyst 3750-48TS, Catalyst 3750-48PS, Catalyst 3750G-24TS-1U, Catalyst 3750G-24PS, Catalyst 3750G-48TS, Catalyst 3750G-48PS and Catalyst 3750G-16TD)
If u want to hold more than 11,000 BGP routes in 3750, only Cisco Catalyst 3750G-12S would be selected.