a. I need to talk to you about something.
b. I need to talk about something to you.
Yes, option "a" seems to be more widespread. I guess "to you" is not really an object but is technically a "complement", a prepositional phrase, just like "about something". But semantically (judged by its meaning) it is an object, and we tend to keep objects closer to the verb.
The second sentence is understandable and probably grammatically correct. But there could be cases where the use of this word order will result in ambiguity:
a. I need to talk to you [about the things they did].
b-1. I need to talk [about the things they did] to you.
b-2. I need to talk about the things [they did to you].
With the word order changed, the majority of people will take the sentence to mean "they did something to you - let's talk about it".
Related:
- A question on word order - ELL
- The Cambridge Grammar of English Language - Ch 4, 4.3 "Ditransitive Clauses" - an explanation of why "to Sue" is technically a complement in "I sent a copy to Sue"