Wait, what's wrong with the 30-speed 105 and Ultegra brifters, and 3x cranks? I have that setup on my Vaya touring setup, and it works great. The stock 6703 triple crank came with a too-big 30t granny on 94mm BCD (meaning you can't go smaller). I replaced it with the 6603 crankset with 74mm BCD so you can go way down (24t running happily on mine, with 39 and 50). There's an equivalent 105 (5603?) and even Dura-Ace triple (7703?) from the same era. I put on a XT long cage derailleur (9-spd so same cable ratio as 10-sp brifters) but that may have been overkill, it seems to have plenty of cage extension left.
12-30 10-sp cassette with 24-39-50 is a really sweet setup - close ratios in back and well-matched for loaded climbing / level and rolling / descending. I did install a chain catcher on the advice of the internet - I mainly found it to wiggle out of place, catch an edge on the chain and twist, and cause a very difficult jam. Took it off and haven't missed it. Probably just needed a rubber shim under it, but again it hasn't seemed necessary.
If tracking down used or NOS 3x10 components and swapping out drivetrain is too much, honestly I could make do with the triple crank with 24 and 39, and a bashguard in the outer spot. Then just replace the crank (possibly BB too) and ride away with your 4700 shifters in 2x10 mode. Someday down the road maybe you find the left shifter and install the third ring.