Can someone who gets the honor of taking out the Sefer Torah also get an Aliyah? I ask because perhaps there is an idea that someone should only get one Kavod by Sefer Torah.
It's possible to run into a situation in which you have no choice but to double up. For an extreme example, suppose you have a minyan of exactly ten men, and it's a Shabbat on which you take out three Torah scrolls. Then, your Torah service honors include seven regular aliyot, maftir, opening the ark, two Torah-carriers, three hagbahas, and three gelilas, for a total of seventeen honors to distribute, meaning that seven of the men will need to get two honors.
(I don't know if I've ever run into a situation this extreme, but I've definitely experienced having to double-up while serving as gabbai at my college minyan.)
I don't have a source to prove that aliya and opening the ark, in particular, can both go to the same person, but it seems, intuitively, that if something has to get doubled-up, opening the ark, which is the honor least coincident with the rest of the Torah service, would be a reasonable choice.