Vrba alone said it´s impossible to coach two teams at once, so I doubt he will take two simultaneous jobs like Weiss did.
Slovak FA isnt in hurry to sign him right now. Hipp will lead squad vs Turkey this month, and next two friendlies are planned in post-season (see #3 above). Vrba can finish the season with Viktoria Plzen and take the job with Slovak NT.
I understand many czech fans are pissed because he was obvious choice for Czech NT in post Bilek era which everyone believes comes to the end after probably unsuccesfull Euro tournament. For Vrba´s personal ambitions, NT it s leap forward. Imagine him having an realistic chance to qualify for Brazil 2014, he would be dumb to turn out such an chance. This is offer he has on table, not some ifs and whens and rumours. He never got official offer to take over Czech NT and if Bilek´s squad will reach some success on Euro, he will be never offered the job. Realistically, he has just same chance to qualify to Brazil 2014 with Slovakia as with Czech NT, at least I dont see potential of Czech squad being much higher than ours.
Sparta ? If he will be succesfull with Slovak NT, he will have much better (or richer, depends on what you likes more) clubs to choose from than Sparta.