extend layer 3 core switch

I need some advice regarding a network conundrum.

Config:

We have 2 core Cisco layer 3 switches (4500's), 1 live & 1 for redundancy.. Fibred obviously,...

1 main & 4 Sub comms racks, which house clustered Cisco layer 2 switches
(Maximum in each rack 3.. 3500's) all these are all linked backed to the core switches)

All ports on the core switches are full.

I need to add another sub comms rack which will eventually house another 3 layer 2 switches.

Question:

Can I extend the present core config and add another layer 3 switch to accommodate the new sub comms fibre link?

I have looked into this, and there does seem a way of doing this, but I need some guidance.

My Solution ?

Purchase 2 more layer 3 switches.

Unattach one of the fibre ports, and plug it into the new core, use one of the ports on the new core and the unattached port and configure these as trunk ports back to the redundant core.

does this make any sense?


Cheers

Screwy

What you are saying should do the trick with the trunk port. You can make a Dot 1 Q trunk back to the main core. If you can give me a current diagram through email and what you want to add to it I might be able to help you out a little better. Are u using 3570 switches as your comms rack switches? Let me know, this sounds similar to a problem I have worked on in the past but a diagram would help me a bit more. Let me know if you are interested and I will give you my email info.