"simple UART"

Is that an oxymoron?

Don't forget that the 'U' in "UART" stands for "Universal".
"Simple" and "Universal" are almost always mutually exclusive! ;-)

"Look at the Triscend 8052 offering - CPLD and 8052 in one package. Also ST do a similar, more secure product."

Absolutely! Why bother with a separate PLD?!
No worries about your extra clocks then!

If security is an issue for you, then look at Steve Knapp's homepage on this site - he has some suggestions.
(me, I come from the world of the 16/32 bit microcontrollers where on-chip Flash was not an option - hence it's not a big issue for me! You get the same issues with any programmable logic device with off-chip configuration memory).

"Triscend do offer a UART with the free IP they supply"

Actually, there's 2 basic "SoftModules"
Full UART has transmitter, receiver, modem-control lines, baud rate generator, control & status registers - very much like a real 16550 chip.
Half UART has either a transmitter or a receiver, without the BRG and modem-control. (there's a separate BRG).

Both are configurable to include FIFOs

"Andy Neil is a great devotee, and he has implemented multiple UARTs in one device"

My current project has a total of 4 UARTs:
The 8032 "standard" UART, 2 FastChip Full UARTs, and a receive+transmit pair of Half UARTs.

See this thread for an estimate of how many you might be able to get into a single device:
http://www.8052.com/forum/read.phtml?id=43154&top=

"My only issue with the Triscends is that they DON'T protect your hardware IP, OR your software IP!"

See my earlier comments!