Buyable blueprints at gun runners for raw cash. Blueprints for sale would be quite random and they would change time to time , let's say 3 blueprint types at a time with a fixed price and amount. Any blueprint could show up for sale , they would cost accordingly to how rare and useful they are ranging from few thousands of caps for some cattle prod BP to 500 k for a combat armor BP.
More alts... bad idea.
This game needs badly random loot on NPCs. So it would be viable to farm some nonsense (meaning, non profitable) encounters . Very slim chance to drop rare items, even BPs, the riskier encounter, the better chance to loot something good.
Secondly, as stated above, randomness in drops will have a positive effect on the amount of players.