do a little more research before you give a definite answer. there is at least one buyable level 10 shield, from the ruiz station (outcast) in omicron beta. brigandine i think, with over 8k shield cap. there may be others, i don't care to befriend corsairs to check their supplies.

Uly, the Adv. Brigandine is L10, with 8280/184, and is a Positron shield. It's sold in 5 places in the game, and is the only L10 shield available for sale. I have never found shields as loot of any kind, and there are lots of rumors flying about regarding shields, such as the mythical 12000/80 Bounty Hunter shield, which doesn't exist.

One location of level 10 shields:

Planet Malta, Omicron Alpha

Guess I was way off. Deleted the 1st part, but the 2nd part still stand:

Go for the numbers, i.e. get graviton shields. Weapons only do 20% more damage against their ideal shields, but graviton are always about 33% stronger than other shield types of the equal level, in effect more than cancels out the damage bonus. Plus there seem to be more factions that use laser weapons than any other types, though I can't say for sure. And on top of that, they're cheaper. Basically, there is absolutely no reason to use a non-grav shield if you have the choice within the same level