Sure, In the Bay Area you can get aged basmati at Vik's Market in Berkeley and various markets in Union City. I would guess any place with an Afghanistan-born enclave would have it somewhere.
In the Bay area the largest concentration of Afghans is in Fremont, there's at least two specialty grocery stores that stock much the same as what you'd see in Kabul.
> Long grain basmati that has aged a couple of years. I dont know if you can find aged basmati in the US.
I believe almost all Basmati rice is aged, the length of aging and of course grades of rice can vary.
You can find it in any Indian grocery store since Basmati grown in India accounts for 65% of the international trade in basmati rice. At least in the Bay Area it can also be found in several/all Costco. Kirkland Basmati rice claims it is aged at least 1 year.