I guess the thing to do is build merged mining ability into your coin from the start but not tell anyone.
Then you can merged mine it alongside the previous oneven the primaty needs support even just for being the primary. Bitcoin has primary support but does litecoin?
If so then yeah, release a merge-able secondary but don't anyone it can be merged mine, so they switch hashing power over to it while you merged mine it with your hashing power that is already mining something else.
I guess first thing we need to know is, have all the existing scrypt coins, or even any of them, inherited from bitcoin the ability to be the *primary* chain in a merge?
I suspect though that the really killer profits are made using CPUs to mine, like the people who mined BBQcoin for many many months back when all the GPUs were ignoring it, and the people who are still mining Tenebrix with CPUs while the people with GPUs are ignoring it. In general, mine the really really easy coins for howerver long you can at low difficulty then profit when peope finally realise it is still around and still accumulating users (grass roots users, folk who don't have mining farms or even, usually GPUs).
Hearing a coin "is dead" is music to the ears of those who only have CPUs or maybe just one GPU, as it doesn't mean dead at all, it means PROFITABLE!
(Remember that to a tiny miner, electricity is ignorable, it might even already be priced into their rent. So they don't care about selling coins to pay for rigs nor selling coins to pay for electricity, they just care how many months they will be able to pick up free coins until the GPU people catch on come back take over and get an exchange set up... The longer that takes the better, in fact best would be if the GPUs don't catch on until at least one block-reward-halving has happened!
)
-MarkM-
