Nowadays there are dozens of new scrypt coins I'd like to mine, but logging in to the miner and changing information all the time is really a pain.
I've been looking for a way to set up a list of pools and let the L3+ mine each coin for a period of time, then move on the next one, and so on. Does anybody knows a way to do this? A software, scrypt, website?
Pool 1 : Coin ABC , stratum+tcp://example.com - mining time 20 minutes
Pool 2 : Coin XYZ , stratum+tcp://example2.com - mining time 60 minutes
Pool 3 : Coin AAA , stratum+tcp://example3.com - mining time 30 minutes
I'd willing to pay for something like this.
Any idea is appreciated.

Not exactly that, but there have been a few pools that allow for mining the most profitable one and keep all:
https://miningpoolhub.com/I've used multipool.us years ago, but it seems down for a while now.
MPH might be a good one to check out, if they have a few options you're looking for. The point is that if you mine for 20 minutes on a coin that has temp high difficulty, then move for 60 minutes to another one that's not "the best at that moment", you're getting little result for your hashes.
Plus, remember that when switching, you'd be losing out on the wrong type of payment for share system (PPS would work best in this case). In a case like that it would be easier to go for for example litecoinpool.org and buy the coins you want with the LTC, as they pay around 300% of regular LTC mining profits.