Low level clan's arnt really catergorised by there levels (As strange as it sounds) and more overall clan strength these days, as I've found.
I don't know when these catergories become gospel, because I find it rather stupid that people say stuff such as "We're not warring you your mid level and we're low level", but thats beside the point.
What is important when considering why low level clans make use of higher leveled accounts way above the clans average is the way in which low level clans war. For most, there clans only events are small 10 vs 10s or even 5 vs 5's in Clan wars, which pretty much negates any reason for levels to stay similar.
A possible explanation is that If you look at the top pure clans, such as FOE, Fi, E, EOP, CP, M etc, all of these started out as "Low level clans" way back when and gradually increased. The fact that the clans are where they are at at the moment is pretty much down to the fact that the clans leaderships realised that they needed to move on from being low levels forever, which explains the difference between Total Domination and these previously mentioned clans, because from what I can recall TD had a fun few weeks then died (multiple times), which I think is down to the fact they planned on staying low level forever. Expansion is often overlooked by the current generation of "low level clans", which results in them staying where they are forever to try and claim some ficticious "#1 LOW LEVEL CLAN!!!!!" moniker.
The introduction of higher leveled clans is some clans ideas of expanding there entire clan, which is flawed for many reasons but I won't get into that here
The above shows the difference in levels Epidemic have had, and the differences. In the first picture, the levels are pretty similar other than the few 60s. In the second picture, the levels range from around 65 - 95, which says alot about the introduction of the CWA.
To answer the question, there really are no low level clans in the mold of Epidemic, The Dreaded, Junior Pures, even Total Domination etc anymore because of the fact there isn't really a point in staying a similar level
Back then, staying similarly leveled was practical. Now, because of the warring habits of "low level clans", it isn't practical its stupid.
Hope I contributed to the discussion a little bit