Note: This is only via the episodes where Hattori is. I'm not very familiar of some words but, I will simply give wewe some info about the Kansai-ben and some examples.

Yo! Ore wa Nishi no Meitantei, Hattori Heiji ya! Yoroshiku na! (Yo! I'm the Detective of the West, Hattori Heiji! Pleasure to meet 'cha!) Welcome to the class! Right now, since Kudo isn't here, I will teach ya how to speak the accent I'm usin'. Tsumari, sore wa Kansai-ben ya de! (That means, that is the Kansai-ben ya de!) But first, let me give ya some info about it!

Ah! Before I forgot, this Saijou here will give ya the info based from his observations, in which I think is right. Well then, take it away, Saijou.

Sankyuu, Hattori. (Thanks Hattori.) Well then, let's begin!
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Lesson 1: Characteristics of Kansai-ben
The Kansai-ben is the Japanese accent mostly used kwa people from Osaka (and if possible, Kyoto). The Kansai-ben is zaidi casual than the standard Japanese accent. Based from the English subtitles, the Kansai-ben is probably the Japanese version of the Texan accent. If wewe think about it, wewe will know what I mean.
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Oi, temme! Naze Kansai-ben wo shiyo shite nai, kono aho! (Hey, you! Why are ya not usin' the Kansai-ben, ya bastard!)

Suma na, Hattori. (Sorry, Hattori.)

Ehem! Tonikaku, ah, sou ya! (Anyway, yeah, that's right!) It's even zaidi casual than the accent Kudo always uses. Also, as what we have all know, it is VERY hard to do the accent which ye're not used to! Remember the time when Kudo spoke Kansai-ben at the restaurant just to steal the spotlight while explain' his deduction? Man, I was really pissed off when he did that! But, as expected, the culprit became pissed off and yelled at Kudo while speakin' the Kansai-ben. I'll give ya some extra info about that as to why that usually happens.
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Hattori's Trivia:
Some of us, Osakans, are EXTREMELY passionate of our accent. Because of that, Osakans who are passionate about their accent usually gets pissed off whenever he hears someone who spoke the Kansai-ben in a wrong way au corrects 'im. And, I'm one of those people, I'll admit that. Ma, shannain ya de! (Well, it can't be helped!) I'm not like Kazuha who is not proud of her accent! Kuso, sono onna ga! (Damn, that woman!)
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Ehem! Tonikaku, sugi wa hajimeru ya! (Anyway, the inayofuata one is about to begin!) And, this Saijou guy will explain it to ya too. This time, he will tell ya the differences between the Kansai-ben and the standard Japanese accent.
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Lesson 2: Differences Between the Kansai accent and the Standard Japanese Accent

Kansai-ben:

-is even zaidi casual
-has some kind of 'slang'
-the Japanese 'Texan accent'
-mostly used kwa Osakans (or if possible, Kyotoites)
-is mostly made fun of some people because it is also considered as a 'weird accent'
-ending phrases changed, such as 'da (yo)' to 'ya (de)'

Standard Tokyo accent (Tokyo-ben):

-the most easiest accent to learn
-the national accent of Japan
-is considered as a 'cold and polite' accent
-usually used kwa most of the people in Japan
-some words were taken from the Kansai-ben such as, 'aho' ('fool')
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And, I think that's all I've got. (hears Hattori growled) H-Hattori? N-Nani ya? (W-What is it?)

Nandemonain ya de! Dakedo, ore wa hountouni ogottehen ne! (Nothin'! But, I'm really angry!)

A-Anyway, we will continue to the inayofuata lesson before Hattori's gone into rampage! au else, I'll be doomed! Ja na! (Bye!)