I'm starting a 16 team dynasty league with minors. I know it isn't a keeper league as you said you were looking for and it is less than you said you were looking for, but this league will be a ton of fun. If you want to spend $100 you can run a Yankees type budget and try to outspend everyone, or you can spend like everyone else if you choose. That's the great part, you can decide how much this league costs for you to be in. Starting lineups are C,3B,CI,2-MI,3-OF,3-UTIL,10-Pitchers with 10 bench spots and 5 IR spots to be used only for actually injured or suspended players. Its a 6x6 H2H with R,HR,RBI,BA,SB,OPS for offense and W+CG+Shutouts,K,ERA,WHIP,QS,2xSaves+Holds for pitching. A small thing, each category is worth 0.62 so that the total regular season games for each team adds up to appx. 162. This is a salary/contract league with a unique feature, you pay for your share of the league salaries. Whatever your % of the league salaries is, that will be your % of the total league buy-in, so you get to set what your buy-in is. Minor leaguers get a league minimum salary with unlimited (until they lose their eligibility) years, but you don't have to own any if you don't want to.
6 team playoff
$200 - Champion
$150 - 2nd Place
$100 - 3rd Place
$50 - 4th Place
$40 - 5th and 6th Place
$30 - Division Champions
$20 - Monthly Best Record (April-August)
There are, of coruse, other rules but if you're interested either respond here or emial me at email@example.com
for more info. I can email you the league constitution with all the details.