As Collin notes, there is a 12 SFP port 3750. Or you use three coppper 3750s that have 4 SFP ports. Or you can mix both in the same stack.
What you might consider, a 3750 is not a 6500. Lots less features and/or capabilities. Except for a very small network, I would be concerned about using it as a core. Perhaps a better choice if you want to use a stackable, would be the 3750-E.
Another possible option for you might be upgrade your sup2 to a sup32 variant. Good chance you'll be able to retain your line cards but you might need a fan upgrade and/or power upgrade.
Many of the 24/48 Ethernet (copper) port 3750s have 2 or 4 SFP ports. E.g. "Catalyst 3750 - 48TS 48 Ethernet 10/100 ports and 4 SFP ports". When you stack 3750s you make one logical device. So, if you stacked three 3750s and each had 4 SFP ports, you would have a logical switch with 12 SFP ports. This then should be able to take the place of the 12 SFP ports your 6500 has now.
Or, since you can mix 3750 models in the same stack (virtual device) a 3750 with 48 Ethernet (copper) ports and 4 SFP ports combined with the 3750G-12S which provides only 12 SFP ports would make for a logical device with 48 Ethernet (copper) ports and 16 SFP ports.
Building a multi-member 3750 stack is much like adding line cards to a chassis, except there is no chassis, but still only one logical device.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
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