I wonder how many people fired up vanitygen trying to find the keys for that one large address? I know it would take millions of years, but you never know, you might get lucky.
That's 340282366920938463463374607431768211456 attempts.
Assuming your computer could try a billion per seconds (it can't, according to the vanitygen
post, vanitygen can do ~20 Million attempts per second on a 6990), that'd still take you, oh,
about 10790283070806014188 years.
...
In other words, chances are you'd witness the heat death of the universe before you actually
"get lucky".
[trolling on technicalities]
Hey! That's only ~10^19 years, ~10^22 years on a 6990.
That's literally nothing compared to the heat death of the universe. (At least 10^40 years.)
Not to mention that there is a lot of headroom between a 6990 and the physical limits to computation.
You have plenty of time, even with a 6990. Better get started.
(You can probably crack it by hand, if the proton doesn't decay.)
[/trolling on technicalities]