you need DATA and CLOCK at 10MHz.

The I see no solution except the SILabs f12x/f13x and (gasp) assembler coding.

The F12x/f13x will give you ~5 instructions pre cycle of the 10MHz, it will be VERY tight, but can (almost) be done. You will need to 'play with' the cache, use well crafted code and I suggest you investigate (I do not know what exactly you need) if you can fit the necessary instructions into the 100ns you will have. I guess that you can get somewhere between 5 and 10 MHz performance, you need to spend some time crafting the code
a couple of tips: you can (re)set the clock together with the data pin load, you need to have the data 'bitmap formatted' (there is no time to format). Is the 10MHz 'ideal' or 'manadatory' i.e. can you get by with 5 or 8 MHz?

poseudocode (incomplete) of one way to do it:
the image is formatted so that all seial data is on bit 0 of the data buffer and bit 1 is always zero

movx, a,@dptr ;get next bit
mov p1,a ; set data, reset clock
inc dptr ;increment dptr and stretch the clock low time
setn p1.1 set clock
sjmp loop ;you need an 'escape when done' here

if you can not squeeze it into a f12x, you will have to abandon the '51 and find another processor.

Erik