I was as surprised as you. I knew Orihime had some feelings for Ichigo - at least in the anime (she kissed him goodbye while he slept before she turned herself over to Ulquiorra) but other than that, the only 'pairing' I could possibly discern had been Karin and Toshiro - which seemed one-sided as well. I thought it surprising when this came up, and I thought the Ichigo was closer to Rukia - but not romantically. I have not read the whole manga though as I was introduced to Bleach through the amime.
Most likely this particular ending was forced on Kubo, seeing as how this is a pretty common thread with mangakas. It seems they don't really have 100% control when it comes to their work. Kubo mentioned at one point in an interview that he had no desire or intention to end Bleach with pairings.
As for Ichigo, the answer is no. At no point in the manga is he shown to have romantic feelings towards anyone. Renji and Rukia made sense, because we were aware of Renji's strong feelings for Rukia. Rukia and Ichigo, I always saw them as having a brother/sister type of relationship, they were buddies, it was never gonna end in marriage and hoards of children.
Ichigo and Orihime just came out of left field. They just stuck Ichigo with whoever was around. If anything, it should have been Orihime and Ishida, it would have made sense. But oh hello, this is a manga, there is no such thing as logic. So, if Naruto ended with Naruto and Sasuke's legacy being carried on by their children, of course Ichigo and Rukia had to get some kids of their own, right? XD Highly predictable and dull, but it is what it is.
Disclaimer: I didn't ship Ichigo with anyone so I have no dog in this fight, I'm just curious.
Here's the thing, I watched the anime until the end and I read the manga until the Fullbringer arc, and now I just read the end. I need someone who has read the whole thing to tell me where does it show that maybe Ichigo had romantic feelings for either Orihime or Rukia. Until where I read I didn't get the sense that Ichigo had romantic feelings for either, they were both his friends (though personally I thought he was closer to Rukia, but again I didn't ship them and I didn't think it was romantic). Whenever his friends were in trouble he would go save them; he saved Rukia in the Ryoka Invasion arc and he saved Orihime in the Invasion of Hueco Mundo arc (they do a lot of invasions don't they?). So my point is, is there any moment or moments were it shows that Ichigo has feelings for Orihime or Rukia. Again, I didn't ship him with anyone, so I'm just curious to see where the sudden romance came from. Thank you and please don't kill me or each other. ヾ(❀╹◡╹)ﾉ~