My game plan has always been to write something for the larger publishing market and to eventually seek a literary agent, but I deliberately started with smaller publishers: partly because of my confidence, partly because some of the things I want to put out probably wouldn't work for anything but a niche publisher (esoteric bits of history and fiction, not anything obscene or illegal like penguin erotica).
I'm signed to put a number of things out over the next two years. The publisher and editor are people I hugely respect, and who I think are very good at their jobs. I got a full length novel out electronically this year, with a print edition to follow next spring. I have two children's books out under a pseudonym that is deliberately easy to link to my other work.
However, my sales are fairly low. I'm aware that you've mentioned on your blog that you do check the sales of authors' other works. I'm trying to improve things, but my publishers are small and I find self promotion really difficult.
Could this sabotage my future attempts to seek representation?
You're no longer a blank slate. You have sales numbers. And they're probably terrible because a lot of small publishers sell direct to readers, and thus the sales aren't recorded on Bookscan.
It's entirely possible to have backlist with a small press and still secure a deal with a larger publisher. You just need a better, faster, stronger, smarter, and more enticing book than everyone else.
In other words, you can hook an agent but you're gonna need a bigger boat.
If an agent/editor/publisher gets excited about a book and thinks they can rake in the cash, nothing silly like a track record is going to hinder them.
Your job, Ishmael, is to get a whale of a project before you start querying agents.