Hi Parvesh,
I am going to assume you have the RSP720 in your 7600 (please confirm if this is correct), in which case the RSP720-3C-10GE supports 128,000 reflexive ACL's and the RSP720-3CXL-10GE supports 256,000 reflexive ACL's. Just for future reference, hardware limitations for things such as max routes, acl's etc can be found in the product data sheet.
In regards to 5000 entires in a single ACL, I cannot confirm if the 7600 will support this, but I don't imagine it will be a problem. You may wish to confirm this with your local Cisco account rep or service engineer. Alternatively if it is under maintenance you could log a TAC case with this question.
I sure do hope that 5000 line ACL is optimized given they read top down and exit on first match (e.g. if the last entire has the highest hit count, you should move it to the top).
Hope that has helped you somewhat with your questions.