Well your best bet for high limits is usually a CU. If you qualify for NFCU, they're quite generous. Alternately, most Amex cards can grow to large limits thanks to the 3x CLI. You can even break past 25k if you're prepared to present your tax documents for income verification.
Prior to my CLI from Amex, Chase gave me my highest limit, but I'd had previous accounts with Chase and do my checking with them, so that may have influenced their decision to give me a larger CL than my other cards.
Thanks
I'm still waiting on Amex they did a FR about 3 weeks ago 
CL $408,200
Looking at your current limits, I doubt any card would throw a 50K limit at you off the bat unless you have very high income.
I have the income.
I landed a 32K initial limit with the Chase Marriott Premier Signature. Not 50k but I think I can make it in three years. Not sure who may issuing that type of credit for a personal credit card.
Thanks,
Maybe I'll try a Credit Union
Well, as you said, if you have the income, AMEX would most likely cater to you, but you'd have to present proof of it, once the CLIs keep coming.
Proof has been sent to Amex Waiting on a response
If you do get the higher CL on AMEX, wait until the new limit reports, and then you will be better off for a decent starting limit.
Thanks
If you have the income, get the CSP from Chase with a high initial credit line and then the Marriott Premier. Once approved for both, you could request to consolidate all of your lines into the CSP. My first round with Chase (CSP) was 28K, a week later they gave me 32K with the Marriott Premier. Both were instant approval.
Thanks, I will look into that