There are several CPLD families that will do what you want, having 5-volt tolerant I/O's and 3V3 core voltage. They are not new, so they're not "bleeding edge" but I've used several different ones at times to effect what I believe you want, i.e. a "245-style bidirectional buffer", but in single configurable bits. The XPLA3 family from XILINX is perhaps the one I've used most, and it's available, IIRC, in an 80-pin package with 128 and 256 macrocells, depending on what you want.

You can use registers not otherwise committed for I/O to build your I2C or SPI interface, BTW. What you basically have to do for each I/O is to combine an 'HC125 and '126 to create your bidirectional I/O. Now, another option, perhaps not any better, is to use the old Spartan-2's, which are still available here and there, and might work for your problem if volume is small and not so cost-sensitive. This family has internal tristate busses available, which might suit your application rather well. These are also available in small packages, and IP (free) for either SPI or I2C is available as well, though that's probably just as readily available for the CPLD's.

I doubt you will REQUIRE 5-volt compatibility, though tolerance is recommended where you drive 5-volt inputs. One nice thing about such parts is that YOU, for the most part, get to assign pinout. Than can be VERY convenient.

RE