IMO, you need a ton of good females to pair up in the future with 1 powerhouse male. The Bamboo project is VERY promising, and would be worth it. If you really want to find "investment" quality BPs, you want to get into the Bamboo, Scaleless, or Highways/Freeways. The GHI train is coming down pretty hard.
Bananas are a decent investment in my opinion. I think they're as big as pieds. The combos sell well (and look amazing), they are one of the most appealing BPs on the market, and they're attainable by many more people who can afford a >$1000 snake than a $10k snake

. The only drawback is the sex-linked issue where males will almost always produce other males. Typically, when you buy a male investment quality snake, you're trying to breed him to produce his replacement... So it kindof works out lol.
Edit: I know this was mentioned, but reptiles aren't a very good investment for a hobby breeder. They do what they want, when they want to, and with who they want to...... It's not clockwork lol.
If you buy animals that you genuinely enjoy, you forget about how much money you spent, and you enjoy raising that animal. Also, I think I talked myself into buying a banana............ Ugh! That itch!