I (we in fact, SG) tried something like that, but we didn't bother building the big pointy thing. Hatchepetsuh was kind and did it for us.
When I saw we were going for egypt, I went all crazy with merchants.
2 GM in a row gave us 2500+ gold each = a bunch of troops.
Aelf is almost right. When you can get good money from it, democracy isn't far away. But not far away isn't eaxctly there, is it ?
Just to be clear : it is not an early game strat. It's only worth it in the late middle age or later.
And DaveMcW is right. US isn't really necessary to begin with. Upgrading dirt cheap units to game breakers is just as good (chariots to cavalry).
Early game, this strat should go :
- pyramids
- representation
- go for engineers/merchants
if engineer, rush a favourable wonder (Great Library! or to a lesser extent, ToA, or sistin chapel for cultural), if merchant settle in your GP Farm or "gold" city (aka shrine + market).
US will only be worthwhile after you have grown towns.
You will not grow towns if you play SE.
Only think about trade mission when you have enough upgradable troops (= 10+ cheap units).
If you count 250 gold for a multiera promotion (axe to grenadiers), you can see where this leads.
A trade mission for less than 2000 gold is a waste IMHO. Better to lightbulb a good tech or settle in your hills city where every food point counts.