Nope, it's not OK. You will sound like a fool. People will obviously get what you want, but it's simply wrong. Btw., thesentence above is also not 100% right, it should be "Ich möchte bitte Herrn Thomson sprechen" or "Ich möchte bitte mit Herrn Thomson sprechen". Besides...I've heard this a bunch of times now, and I still have no clue where it's coming from, but I'd say it's not true that German sentences usually end in a verb.

The verb in the present and past tenses will not appear at the end of the sentence,when the verb stand solely on its own. In fact a verb will appear at the end ,when there is already another primary verb at the first part of the sentence. In cases of : - Using the Perfect tense: Ich habe das Buch gelesen. (habe) as the verb used to form the Perfekt tense plus the Partizip ( ge + lesen). - Using auxiliary verbs in general as mentioned above: müssen, können, wollen , möchten usw... wie in deinem Beispiel Ich möchte bitte mit Herrn Thomson sprechen. You never put the 2 verbs subsequently ,it is wrong as you wrote it Ich möchte sprechen Herr Thomson bitte. (That is totally wrong). Notice ,that as long as there is an object or more than one ( direct or indirect) ,the second verb will come after them, in case there is no object ,and only in this case you place the 2 verbs subsenquently as in: "Ich möchte sprechen." *( Das steht aber selten allein). - When you use the future tense in the form of (werden + verb im Infinitiv): Er wird ihn bald anrufen. Never say : Er wird anrufen ihn bald. Wie gesagt der Object kommt inzwischen und der Verb meistens am Ende des Satzes. ** Merk dir auch : Das Verb am Ende des Satzes steht immer entweder im Infinitiv oder Partizip form (ge+Verb im Partizip).

I'm not sure what you mean by "sentence topic", and how it relates to your question. Anyway, in main clauses, the verb is *not* written at the end. It's usually in the second position: "Ich spreche mit Herrn Thomson". If you add an auxiliary verb like "wollen", "können", etc., then this auxiliary verb is in the second position (and conjugated), and the original verb (but only that) moves to the end: "Ich möchte mit Herrn Thomson sprechen". "Ich will nach Deutschland reisen". etc. So the most you can do is to move the "bitte" in various positions: "Ich möchte bitte mit Herrn Thomson sprechen." "Ich möchte mit Herrn Thomson sprechen, bitte." are both ok, but your example ist just wrong.

Sentence topic in German is the same as in English. As for word order, German has its rules. If you don't follow the rules then it is wrong. Simple as that. Why ask questions about them?

That's like to ask why in english the adjective goes before the verb instead of after it (as in spanish)?? That's a feature of the language...