If I have a Windows 7 64-bit system with RAID-10 and OCZ 128GB Synapse Cache drive for caching, will I have to totally redo my setup if I do a total install of Ubuntu 12.04?
If we assume that you are trying to add Ubuntu as a second bootable OS along side Windows - then the answer is going to depend on whether that clever RAID-10 setup can be reduced in size and split into two partitions. Alternatively, on whether you can install additional drives.
One comment before continuing. RAID-10 is a very expensive option are you sure that you really need it?
Anyway, the answer is that you either need to be able to reduce the size of the RAIDed partition and split it so that you can create at least one or two new partitions. Or you need to install a new drive (or 4 if you insist on RAID-10'ing everything for some odd reason).
In either of these 2 cases, you can install Ubuntu along side the existing Windows installation. In either case, it will be easiest to ignore the SSD for Ubuntu.
The one remaining difficulty will be where the Master Boot Record will reside. Assuming you have a reasonable PC with a good BIOS, you should be able to swap around the disk priority, in that case, it is easy if you have installed a new disk because you can make the new disk a higher boot priority in the BIOS and install the new Master Boot Record there. The Ubuntu install should pick up the existing Windows boot record and add an option to boot Windows into the Grub boot menu. If it doesn't you will need to look up how to add it manually - this might happen with such a complex setup.