Opposite of the suffix -less
Solution 1:
There is no universal affix in English equivalent to the German suffix behaftet.
Instead, there are two different ways to form this kind of adjective in English.
The suffix -ful suggests that the noun modified has the quality in question in abundance. It is a limited suffix that can be used only with certain words: hopeful, but not hungerful.
The past participle of some verbs can also be used as an adjective. For example, the opposite of "stainless" is "stained." Again, this does not work with all verbs, and I'm not sure what the rule is. It seems to be more common with transitive verbs ("stained," "baked") but also includes some intransitive verbs ("fallen," "wilted"). It cannot be used with nouns, but is often used with words that share a noun and verb--all four of the examples above fall into this category, and it may in fact be a requirement.
Your specific examples don't fall into either category. They're both nouns, so the verb tense trick doesn't work. ("Dimensioned" is a word but suggests "having been dimensioned" rather than "having a dimension.") And neither is on the -ful list.
So you have to use a multi-word construction instead of a suffix. This is pretty common in translating from German, which, from a native English speaker's perspective, seems to have an affix for just about everything.
Solution 2:
Without commenting on the more general forming of anti -less terms, you could consider unitized and dimensional.