A lot of these women posted here (Charla included) outside of their excellent biceps are not very heavily muscled elsewhere. This is due to their personal focus, fitness, physique, or (early) bodybuilding so I put them together. Some other match ups come to mind when considering women with a little more overall muscle. Renee would probably crush anyone including Kim Perez her only real competition. Michelle might have a good battle with say, Lindsey Mullanazzi or a whole host of other women. Along these same lines, though Marja is quite small. so someone like Denise Masino might be a could fit for her. Then we have tall women like Shawna Walker and Shawn Tan...
In the early days of fbb, as other threads here have discussed before, we had mostly nicely muscled women who either had great bicep genetics (Charla!) or worked extremely hard their biceps as it was a focal point for judges at the time. The "golden age" if you will. As time progressed the sport evolved into supporting bigger and bigger women overall, though as it stands it does appear there is a limit as Renee's track record clearly shows.
So for me personally, it's about overall proportion when I see a great bicep. That is the size of the bicep compared to the overall individuals body type/size, then the bicep size, shape, and height to some extent. As I think about others like Klaudia Larson or Joan Lauth, they're both anomalies. When Klaudia was a bit smaller body wise she rocked and her bicep shape had very few to compare her with as is still the case today, though she's packed on a lot of size. It's a similar case with Johanna Dejager too. She's small, not heavily muscled and has got a huge bicep that is so round and beautiful it's hard to find a similar match up. She's got a bicep that is sort of like Klaudia's but it also isn't too. So, for example, do you throw Klaudia up against Michelle? To me they're both biceps, but different enough too that maybe a better match could be found. Yet another way to look at is this; Macey doesn't impress me much when you see her inside bicep shots, but her backside shots look to give Michelle, Klaudia, or Donna Bramble a run for their money when viewed that way. This is where both Klaudia and Charla impress, inside and outside yet are not very similar other than in height (bicep and body wise).
To wrap up here, Charla's competition for many has been Mindi in recent years. In her past it was really Linda Bevelander. Jodi's arm size and body type make her a great match up for Heidi and Dana Linn, though Dana Linn is smaller and Heidi's biceps tend to have a flatter plateau'ed type of peak.
In my mind I have all sorts of match ups to bring to this board. How about Tori Stroud and Michelle Roth? To me, that's a good one. Or, Macey (backside) vs. Donna and/or Michelle, Lindsay Mullanzzi, Elena Seiple, then Jodi Miller vs. Amanda (Swallow) Hatfield. The combinations and possibilities are endless...
More to come, keep watching!