shinmeikai: ただ単にそうしただけでも。「見る―かわいらしい」
daijr:  二つの事柄が必然的に結ばれており，それらが相続いて発生するという意を表す。「からに」の形をとる。「…だけの理由で」「…ばかりで」の意。「見る―に強そうな人」

I think it's always used with て. Perhaps the headword should be てからに like in the kokugos.
There's another unrelated meaning.

@@ -9,2 +9,7 @@
-<s_inf>oft. as 〜てからに at the end of a sentence</s_inf>
-<gloss>expresses dissatisfaction or criticism</gloss>
+<s_inf>as 〜てからに at sentence end</s_inf>
+<gloss>expresses displeasure or disapproval</gloss>
+</sense>
+<sense>
+<pos>&exp;</pos>
+<gloss>just from (doing)</gloss>
+<gloss>simply by</gloss>

Maybe. Daijisen quotes the 浮世風呂, which is hardly contemporary. It's hard to form a view of how common it is in that context. It's in just the one Tanaka sentence, AFAICT.

might it be archaic outside ksb?

Koj, Daijr/s
Tanaka: あの政治家のらりくらりしよってからに。 The politician is as slippery as an eel!

The kokugos just explain it. No sign it's limited to Kansai

@@ -8,3 +8,3 @@
-<pos>&prt;</pos>
-<dial>&ksb;</dial>
-<gloss>(as 〜てからに at the end of a sentence) expresses dissatisfaction or criticism at the listener</gloss>
+<pos>&exp;</pos>
+<s_inf>oft. as 〜てからに at the end of a sentence</s_inf>
+<gloss>expresses dissatisfaction or criticism</gloss>