I'll go out on a limb and say no, there aren't any such studies. You've already asked for a list of Swadesh lists here, so presumably you're going to make that analysis yourself on those.
The uselessness of Swadesh Lists
There's also the question how much use Swadesh lists would be for that. Swadesh lists are claimed to be a measure of genetic relatedness of languages since the words on that list supposedly are slow to change and rarely borrowed. If you intend to use word lists, better use the whole dictionary instead: the greater number of words means that your result is more statistically reliable. It doesn't matter that you don't have the same words for each language, since you'd give the number of vowels as percentage of the sounds of the whole lexicon or something, which makes it comparable.
Of course, the lexicon would contain both common and rare words - by Zipf's law mostly the latter, so that might skew things. However, the Swadesh list is not the list of the most common words but has, as mentioned, a different purpose. So for a realistic appreciation of sound distribution I recommend you get a corpus of each language: that would be representative of actual speech and thus be a better data source for what you intend to achieve.
The relevance of syllable structure
I've never heard anyone saying "that language is only incomprehensible vowels". Any examples about which languages that was said of? Though generally people latch onto some characteristic they believe to perceive when in fact it is not as prominent as it would appear - there presumably exist studies on that, but you'd have to ask on this stack exchange.
If we knew what language you spoke of, then one could shape a hypothesis that could be otherwise tested. I consider it likely that syllable structure (map) is relevant: e.g. Hawai'ian has a simple syllable structure, Japanese a moderate and English a complex one. Languages with a simple (or moderate) structure presumably sound more vowel-heavy - especially to languages with complex syllable structures like English which allows syllables like strengths (CCCVCCC).