First the 4006 vs. 4506.
4506 can have two PSUs running 1+1 redundancy. The 4006 can have three PSUs for 2+1 redundancy (it needs two to run). In practice, that means you need three separate power groups to achive redundancy for the power with the 4006, but only two with the 4506.
4506 can provide inline power using only the two internal power supplies (not the 1000W PSUs, though). The 4006 needs an external power chassis to provide inline power. Adding inline power to the 4506 is much cheaper than with the 4006.
4006 is slightly smaller than the 4506 (40x43.7x30 cm vs 44.13x43.97x31.70 cm).
Finally, the 4506 is 'the new box' and I wouldn't rule out the possiblity that features might be implemented on the 4506, that can't be implemented on the 4006.
I would go with the 4506.
Second, the Sup2 vs. Sup3/Sup4.
First, Sup2 is a 'pure' L2 supervisor. It won't do stuff such as ACLs and QoS based on L3 or L4. Sup3/Sup4 are of cause true 'L3 switches' (routers) and also have strong ACL and QoS capabilities.
Second, Sup2 is conceptually three separate 12 Gbps switches, which are interconnected with 1 Gbps connections. Depending on your traffic pattern, that could lead to *heavy* internal blocking. In contrast, the Sup3/Sup4 are true 32 Gbps switches (marketing would call that 64 Gbps, of cause), providing 6 Gbps non-blocking to each blade, plus two on the Sup itself.
Oh, and the Sup2 runs CatOS, which Sup3/Sup4 runs IOS.
Whether the Sup2 or Sup3/Sup4 would be appropriate, depends on what you're expecting it to do. Sup3/Sup4 will do inter-VLAN routing, and will do so at (close to) wire rate. The 4232-L3 is slower and 'only' does L3 via the two 1G connections to the backplane.
If you go with the L3 supervisors, pick the Sup4. It does all the Sup3 does and then some (faster CPU, possibillity to do NetFlow accounting, can be run redundantly in the 4507R chassis). And they're 1,5 k$ cheaper than the Sup3s, so to me that choice is a no-brainer.
-A
