First, to answer one of your questions, I would say that most banks and credit unions in the U.S. do offer HSA accounts.
When selecting an HSA, it comes down to how you intend to use it.
Some people (like myself) have a lot of medical expenses, and not a lot of extra cash laying around. For those of us in this situation, the interest rate/investment options of the HSA are not important, as the money will not be sitting in the HSA for long. Instead, the most important features we are looking for are low fees, ease of use, and customer service. By looking at your local credit unions and banks to see what they offer, you will probably find something in your area (perhaps with the same institution that already provides you with a checking or savings account) that is a good fit for you. Look for something with no on-going fees.
Be sure to ask about how to reimburse yourself/take distributions from the HSA. I prefer a credit union that does not restrict my access to the money in any way. I can take a distribution by using a debit card, writing a check, going to the website and transferring money to my checking account, or even by showing up at the local counter and withdrawing cash. My credit union never asks me to justify a distribution by showing a medical expense receipt; the responsibility to ensure I am using the funds in a tax-penalty free way is entirely mine. Some people may not like this freedom, preferring a bank that will protect the customer from making mistakes, but I prefer to keep track of my own expenses and receipts. You should choose an HSA institution that makes using the money easy for you, however you define that.
Some people are in the fortunate situation where they don't forsee using much of their HSA contributions for many years. These people want to look for an HSA account with investment options, and are not so concerned with having local customer service, instant access to the funds, or with small fees associated with small balances, etc. If this is you, and you see the HSA as an investment vehicle, then perhaps the local bank/credit union is not the best place to look. Instead, you might want to look at large, national providers. Perhaps you can look to your brokerage or mutual fund company to inquire about HSAs. For example, Fidelity offers their own HSA, and Vanguard, while not offering an HSA of their own, has a page listing HSA providers that allow investments in Vanguard funds.
In conclusion, decide what your goals are for the HSA, and then you can find an HSA that will help you meet those goals.